Аннотация:Results of studying tandem reactions—aldol–crotonic condensation and hydride transfer hydrogenation—in an acetone–isopropanol mixture in the presence of an MgSnO3 catalyst at 300–400°C and 12.0 MPa are described. Under these conditions, a mixture of the substrates and reaction products is in a supercritical state. The temperature dependences of the conversion of the reactants (acetone, isopropanol) and the selectivity for condensation and hydrogenation products are discussed. It is found that the hydrogenation of products of the aldol–crotonic condensation of acetone occurs via the addition of hydrogen from isopropanol molecules via the C=O bonds of isomeric mesityl oxides and phorones and is accompanied by the alcohol dehydration and C=C double bond isomerization reactions. The optimum conditions for the formation of the carbonyl group of hydrogenation products are 350°C and an acetone : isopropanol ratio of 7 : 3. At an acetone : isopropanol ratio of 1 : 1, methylpentadienes are dominant in the mesityl oxide conversion products. The hydrogenation reaction also involves isophorones, i.e., the condensation products of three acetone molecules.
